APA

Schulzinger R. D., . (1984). American diplomacy in the twentieth century. New York: Oxford University Press.

Chicago

Schulzinger Robert D, . 1984. American diplomacy in the twentieth century. New York: Oxford University Press.

Harvard

Schulzinger R. D., . (1984). American diplomacy in the twentieth century. New York: Oxford University Press.

MLA

Schulzinger Robert D, . American diplomacy in the twentieth century. New York: Oxford University Press. 1984.